Being a novice and completely amateur photographer i have been tinkering with a compact camera underwater... ocasionally i manage to take a good photo, but most of them are somewhat blurred, specially if i turn off the flash and use ambient light.

Your English is fine and so are the images...I could not find to many blurry ones. The focus looks great. Which images exactly are you concerned about?The flash does allow the camera to freeze the image. Without the strobe, shutter lag may come in to play more, especially if coupled with slower shutter speeds (if you are shooting manual)or if the camera on auto and a macro mode picks a higher f stop and sacrifices for a slower SS.